Testing apparatus and method for detecting a contact deficiency of an electrically conductive connection

ABSTRACT

A testing apparatus and a method for detecting a contact deficiency of an electrically conductive connection. The testing apparatus comprises a measuring chamber, in which several system elements of the connection that are connected in an electrically conductive fashion are positioned, a heat radiator that is supplied with energy and the transferred thermal radiation of which is emitted into the measuring chamber and directed toward the region of the system elements that, after having been heated, generate a thermal field of the insulated and the metallic system components of these connected system elements, a thermal (image) acquisition unit for optically capturing the generated thermal field and for realizing a signal conversion into a thermal image of the connected system elements, and a thermal (image) reproduction unit for the visual reproduction of the converted thermal image.

FIELD OF THE INVENTION

The invention relates to a testing apparatus and a method for detectinga contact deficiency of an electrically conductive connection accordingto the preambles of claims 1, 2 and 23. It is intended for applicationsin which such connections need to be produced in a very precise andquality-responsive fashion in order to ensure the constant availabilityand reliability of the electrically conductive connections in the supplyof energy to electric consumers and/or the transmission of informationto control units or other devices, for example, in aircraft. Theinvention realizes a prophylactic testing of such electric cableconnections that are prefabricated due to technological considerationsand allows a reliable visual detection of incorrectly (defectively)produced cable connections without significantly technologicalexpenditures.

BACKGROUND TO THE INVENTION

It is generally known that vehicles such as land craft, watercraft oraircraft are equipped with a plurality of electric connections that needto be produced in a very precise and quality-responsive fashion for theinitially cited reasons. Conventional cable connections, theinstallation of which is realized with copper cables, are quitefrequently produced with copper cables, the conductor of which isrespectively connected by crimping a metallic crimp type socket on thestripped conductor region with the aid of a suitable tool, wherein theelectric connection between to strip conductor ends accommodated in thesockets is ensured, for example, by the socket making contact with theconductors. This contacting is predominantly realized with said crimpconnection, wherein conventional systems may include this installationtechnology. In order to ensure that a reliable electric connection isproduced, crimp type contact sockets provided with a recess in the formof an inspection hole are used, for example, in the construction ofaircraft, so as to determine whether or not the copper conductors of twocopper cables are correctly connected to one another by means ofcrimping. In this case, (only) a visual inspection may be carried outafter the crimping process so as to ensure that the crimping process wasperformed properly, wherein the crimped conductor needs to be visiblewithin the region of the inspection hole if the contact socket wasproperly crimped. Since visual errors of the individual inspectors ormaterial defects on the contact socket or an inspection hole positionthat deviates from the predefined position (due to the defectivemanufacture of the contact socket), among other things, may never beruled out, the question whether this testing technology actuallysuffices is not discussed in detail because the proposed inventionpursues a profoundly different goal. Corresponding examples of suchcable connections are illustrated in enclosed FIGS. 1 and 2 in order toprovide the observer with a practical overview of the relevant design.

With respect to aircraft, the invention also takes into considerationinstallations with cables, the conductor material of which may result ina weight reduction, namely because any weight reduction is a desirableaspect, particularly in the construction of aircraft, for example, dueto the attainable energy savings (kerosene consumption) and the extendedrange of the aircraft.

When utilizing a technology of this type that takes into account theinstallation of such weight-reducing cables in aircraft, it may benecessary to utilize crimpable contact sockets that do not contain aninspection hole. The reason for the lack of the inspection hole may beseen in that the contact areas of the connecting points may need to behermetically sealed in order to reliably preclude any corrosion of thecrimp connection and/or an increase of the electric contact resistancesat the contact points. Corrosion may be caused by various types ofmaterials (silver, copper, nickel, aluminum), wherein the reason forthis corrosion may be seen in that the connection(s) is (are) producedwith (a) cable(s) and a contact socket of different conductivematerials, as well as in the local influence of an electrolyte inconnection with (occurring) humidity, for example, atmospheric:humidity. In this respect, in conventional systems corroding contact(s)(surfaces) may lead to the failure of the connected devices andapparatuses or even entire systems, wherein this may, in the(undesirable) worst-case scenario, result in the complete failure of the(correlating) systems in the aircraft. The consumption of a corroded,current-carrying contact caused by an increased (growing) electriccontact resistance may have fatal consequences. The increase of thecontact resistance at the contact points of the electric connection inquestion may therefore also be influenced by the improper crimping ofthe contact socket on the conductor regions to be connected. If thecontact surface has excessively small dimensions, the current densityincreases such that said consumption may occur on the contact surfaces.If the contact socket is improperly crimped such that the connectingelement(s) (surfaces) are insufficiently contacted, it may be expectedthat any occurring vibrations, for example, those of an aircraft, willresult in the failure of the devices, apparatuses or the entire systemconnected with the aid of this crimp connection. The aforementionedinferior contacting in a conductor-crimp type socket-conductorconnection may be decisively influenced by the improper crimping of thecontact(s) (surfaces) of the connecting elements and/or by theinadequate insertion of the cable(s) into the contact sockets, whereinin conventional systems these inadequacies are named under the term“contact deficiency” of the electrically conductive connection. Theillustrations in enclosed FIGS. 3A, 3B, 3C and 4 show examples of aconnection that is produced correctly or incorrectly, wherein acorrectly produced connection (correctly stripped) is illustrated inFIG. 3A. The incorrectly produced cable connections shown in FIGS. 3B(over-stripped), 3C and 4 (incorrectly cut and inserted cable) elucidatethe existing need (appreciation) to solve (eliminate) the problemdefined below.

SUMMARY OF THE INVENTION

Among other thinks, it may be an object of the invention to makeavailable an efficient solution for a testing apparatus and a method fordetecting a contact deficiency of an electrically conductive connection,wherein said solution may make it possible to verify whetherprefabricated cable connections or subsequently produced cableconnections as they are required during repair procedures or adaptivemodifications are produced in a precise and quality-responsive fashion.The invention may aim to disclose a reliable visual detection ofincorrectly (defectively) produced cable connections, wherein thehandling of the testing apparatus and the implementation of the methodmay be realized without significant technological expenditures.

This objective is attained with the characteristics disclosed in claims1, 2 and 23. Embodiments of these measures are disclosed in theremaining claims.

According to an exemplary embodiment a testing apparatus for detecting acontact deficiency of an electrically conductive connection is providedwherein the testing apparatus is realized with several electricallyconductive system elements for conducting signals or energy, wherein ameasuring chamber is provided in which are positioned the systemcomponents of the connection that are connected to one another in anelectrically conductive fashion, wherein a heat radiator is providedthat is supplied with energy and the transferred thermal radiation ofwhich that is emitted into the measuring chamber is directed toward theregion of the system elements such that a thermal field of the insulatedand the metallic system components of these connected system elements isgenerated, wherein a thermal (image) acquisition unit is provided thatserves for optically capturing the generated thermal field emitted bythe heated insulated and metallic system components of these connectedsystem elements and for realizing a signal conversion into a thermalimage of the connected system elements, and wherein a thermal (image)reproduction unit is provided that serves for realizing a visualreproduction of the converted thermal image, with the thermal (image)acquisition unit and the thermal (image) reproduction unit beingconnected in an information technological manner.

According to an exemplary embodiment a testing apparatus for detecting acontact deficiency of an electrically conductive connection is providedwherein the testing apparatus is realized with several electricallyconductive system elements for conducting signals or energy, wherein ameasuring chamber is provided in which are positioned the systemcomponents of the connection that are connected to one another in anelectrically conductive fashion, wherein a heat radiator for infraredlight is provided that is supplied with a constant current by agenerator, wherein the infrared light thermal radiation of said heatradiator that is transferred transversely or horizontally or verticallyor in a deflected fashion is directed toward the region of theelectrically conductive connection such that a thermal field of theinsulated and metallic system components of these connected systemelements is generated by the infrared light thermal radiation, wherein athermal (image) acquisition unit for infrared light is provided thatserves for optically capturing the generated thermal field and forrealizing a signal conversion into an infrared light thermal image ofthe conductively connected system elements emitted by the heatedinsulated and metallic system components of these connected systemelements, and wherein a thermal (image) reproduction unit for infraredlight is provided that serves for realizing a visual reproduction of adigitally converged thermal image, with the thermal (image) acquisitionunit and the thermal (image) reproduction unit being connected in aninformation technological manner.

According to an exemplary embodiment a method for detecting a contactdeficiency of an electrically conductive connection is provided thatserves for the testing of the electrically conductive system elementsused for conducting signals or energy, wherein several seriallyconnected system elements are connected in an electrically conductivefashion by means of a crimp connection at the connecting points of thesystem elements, wherein said method utilizes a testing apparatus, thefunctional scope of which comprises a measuring chamber, a heat radiatorthat is supplied with energy and arranged within the latter, a thermal(image) acquisition unit and a thermal (image) reproduction unit thatare connected with respect to information technology, and

wherein the following steps are carried out:

-   a) the system elements that are serially connected by crimp    connections are positioned in the measuring chamber and subsequently-   b) the heat radiator in the measuring chamber directs transferred    thermal radiation toward the region of the system elements, namely    such that subsequently-   c) the insulated and metallic system components of the connected    system elements absorbs the transferred thermal energy of the    thermal radiation converting to a thermal field and subsequently-   d) the thermal (image) acquisition unit optically captures and    subsequently converts the generated thermal field by a signal    conversion into a thermal image and subsequently-   e) the thermal (image) production unit realizes a visual    reproduction of the converted thermal image.

At this point it has to be mentioned that the described testingapparatus may also be realized by means of further embodiments. Thereby,it is clear for a person skilled in the art that the features describedwith these further embodiments may also be combined with features of theembodiments described above and the embodiments for the method fordetecting a contact deficiency of an electrically conductive connection.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, for further explanation and for better understanding of thepresent invention, exemplary embodiments are described in more detailwith reference to the enclosed drawings. In the drawings:

FIG. 1, shows a cable connection with a copper conductor and a contactsocket;

FIG. 2, shows the cable connection according to FIG. 1 with an aluminumconductor (with a copper and/or nickel coating of the bunched wires ofthe aluminum conductor) that is accommodated within a silver socket;

FIG. 3A, shows a correctly produced cable connection according to FIG. 1with a conductor insulation of an electric conductor that isaccommodated at the beginning of the socket;

FIG. 3B, shows a cable connection according to FIG. 3A with severalcontact deficiencies;

FIG. 3C, shows a different illustration of the cable connectionaccording to FIG. 3B;

FIG. 4, shows a detailed illustration of the cable connection accordingto FIG. 3C;

FIG. 5, shows a physical illustration of a testing apparatus for testingcable connections;

FIG. 6, shows the block diagram of the testing apparatus according toFIG. 5;

FIG. 7, shows an embodiment of the testing apparatus according to FIG.5, and

FIG. 8, shows a modified embodiment of the testing apparatus accordingto FIG. 5.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

It should also be noted that the contact socket 71 in FIGS. 1 and 2 isrespectively equipped with an inspection hole 75 that traditionallyserves for visually inspecting (verifying) an electrically conductiveconnection 5 in the socket. In other respects, these conductorconnections according to FIGS. 1-4 generally pertain to the(conventionally implemented) state of the art while the testing of theseconductor connections that is described below and carried out by meansof the testing apparatus 1 according to FIGS. 5-8 may aim to eliminatethe deficiencies that are (obviously) inherent to traditionally utilizedtest technologies (in need of improvement) according to FIGS. 1-4 (fortesting such conductor connections). In order to clearly elucidate theproblems inherent to this state of the art to a person skilled in theart, a few additional explanations deemed necessary for the betterunderstanding of the following exemplary embodiments of the inventionare provided below with reference to FIGS. 1-4.

In conventional systems conventional conductor connection according toFIG. 1 may be known. This connection features a contact socket 71, thesocket cavity 72 of which on the left side (clearly highlighted) ispartitioned approximately in the center of the socket. Consequently, thethusly partitioned socket region (socket cavity 72) may be compared witha socket outlet 74 that is closed in the center of the socket and atwhich the contact socket 71 (shown on the left) ends (approximatelyabove a socket flange 76 on the circumference of the socket), whereinthe right sleeve-shaped socket region of the socket according to FIG. 1embodies another contact socket 71A for producing another electricallyconductive connection.

In the sleeve-shaped socket regions of the socket that lie to the leftand/or the right of the socket flange 76 or at the opposite socketinlets 78, 78A, respectively, it may therefore be possible to insert thestripped conductor region of a conductor 61 that is referred to as thefirst system element 6 and/or a conductor 81 that is referred to as thethird system element 8 into the respective socket cavity 72, 72A and toguide this (stripped) conductor region along the socket axis (of theentire socket) as far as the end of the contact socket 71 that is closedin the center of the socket or the socket outlet 74, respectively (suchthat it is contacted by the conductor end). According to the exampleshown in FIG. 1, an electric conductor 61 that is realized in the formof a nickel-coated copper conductor and referred to as the first systemelement 6 should only be connected to one side of the contact socket 75that is referred to as the second system element 7.

The conductor insulation of the copper conductor may conventionally notbe inserted into the socket cavity. A more detailed description of(other) distinguishing peculiarities of cable installations is providedfurther below.

The electrically conductive connection according to FIG. 1 produced bycrimping the contact socket 71 on the conductor end region accommodatedin the socket with a suitable crimping tool may be accepted by a personskilled in the art as a correctly produced “conductor-socket connection”or a flawlessly produced “electrically conductive connection 5.” Aglance into the inspection hole 75 provided on the contact socket 71enables the inspector to visually inspect each copper conductor andtherefore makes it possible to verify that the connection was correctlyproduced.

According to the example shown in FIG. 2, it is may be known to connecteach aluminum conductor that is realized with a copper and/or nickelcoating of the bunched wires of the aluminum conductor to a contactsocket 71, the socket material of which significantly differs from thatof aluminum according to the may be known “electrochemical series”. Suchcable connections that are produced with system elements 6, 7 ofdifferent materials may ultimately be destroyed because the materialdecomposes due to the inevitably occurring (unavoidable) electrochemicalcorrosion of the (initially realized) electrically conductive connection5. However, embodiments of cable connections may also be known (forwhatever reasons), in which the thusly connected system elements 6, 7are realized with a silver socket 141 that adds yet another differentconductor material and is referred to as the fourth system element 14.The latter is arranged along the socket axis of the contact socket 71,the conically shaped socket head of which adjoins with its cone pointthe closed socket end (socket outlet 74) that is positioned in thecenter of the contact socket 71 and appropriately adapted to the conicalshape.

In addition, it is amazing but true that, for example, the strippedconductor region of the aluminum conductor is positioned along thesocket axis of the silver socket 141, wherein the electricallyconductive connection 5 of a thusly realized arrangement is produced bycircumferentially crimping the contact socket 71 on the silver socket141, the crimping of which is transmitted to the stripped conductorregion of said aluminum conductor. A few questions may remain unansweredthat exceed the broader scope of the description, namely because it isnot discussed, for example, whether the silver socket according to thepresented arrangement of the system elements is able to delayelectrochemical corrosion for a sufficiently long time; or whether thecrimping pressure exerted upon the contact socket 71, for example, witha manual crimping tool may be transmitted with sufficient intensity tothe aluminum conductor used as the electric conductor 61. In any case,FIG. 2 makes one thing clear: it may be impossible to make anystatements that readily provide answers to such questions as: “How deepwill said copper conductor be seated in the silver socket?” or “Whatmaintainable distance will the end of the aluminum conductor have fromthe closed socket outlet 74 (situated approximately in the center of thecontact socket 71)?” It may remain a fact that the inspection hole 75 ofthe contact socket 71 may obstructs the view of the aluminum conductorthat remains blocked by the additional arrangement of the silver socket141.

We hope the reader will not be disappointed because no additionalembodiments are discussed that feature another duplicate silver socket141A arranged on the socket axis of the contact socket 71 in the form ofa mirror image of the aforementioned silver socket 141.

The reason for this is correlated with the repeated mentioning of theabove-described disadvantages (of the same type) of a crimpablearrangement (shown on the left) of the system elements according to FIG.2 that may occur as predicted if an additional copper conductor isconnected to the socket in order to produce an electric cable connectionof the conductor-fitted contact socket 71, for example, with otherdevices, apparatuses, etc.

These disadvantageous deficiencies of the aforementioned cablearrangements also apply to known electrically conductive connections 5according to the examples shown in FIGS. 3A, 3B, 3C. However, certaindifferences may exist (in comparison with the description of theembodiment according to FIGS. 1 and 2), according to which adefinitively limited insulation region of the conductor insulation 62 ofan electric conductor 61 that is referred to as the first system element6 is arranged underneath a predefined socket (crimping) surface. B ofthe contact socket 71 so as to prevent or at least restrict anadditional admission of moisture or other liquid or gaseous fluids afterthe contact socket 71 has been (sufficiently?) crimped on the conductorinsulation 62 inserted into the socket. The question whether thismeasure may suffice is not discussed further.

In a thusly crimped connection 5 that is realized, for example, with anelectric conductor 61 and a contact socket 72 that both consist of analuminum material, however, it may be impossible to visually verify thatthe end of the electric conductor 61 accommodated in the socket actuallyextends as far as the closed socket end (socket outlet 74) or wasarranged such that it adjoins or is positioned a tolerable distance Δ1from this socket end, respectively. The closure of the socket outlet 74(i.e., the end of the socket) would be situated underneath an exemplarysocket flange 76 that is annularly arranged on the circumference of thecontact socket 71. Although the contact socket 71 features an inspectionhole 75 (a contact hole for a visual inspection) at a defined location,this inspection hole is covered by the auxiliary socket 141 used that isrealized in the form of a silver socket such that no visual inspectionmay be carried out in order to determine whether the electric conductor61 is at least arranged in the socket within the permissible tolerancerange. This is the reason why one utilizes correspondingly positionedmarkings 63 that are (circumferentially or pointwise) arranged (in aclearly visible fashion) at a defined location of the conductorinsulation 62 in order to ensure the required length measure of theconductor insulation 62 and of the electric conductor 61. However, itmay not be ruled out that cable connections 5 realized in accordancewith the arrangements in FIGS. 3B and 3C are produced because individualor mechanical installation errors may still occur. A correctly producedembodiment of a crimped conductor-socket connection with aluminum systemelements 6, 7 is illustrated in FIG. 3A. In comparison with correlatingFIG. 3C, FIG. 4 provides the observer with a more detailed overview ofan incorrectly produced connection 5.

The preceding (general) remarks regarding the state of the art areprovided for the better understanding of the testing apparatus 1described below (with reference to FIGS. 6-8) and the method fordetecting (identifying) a contact deficiency of an (already crimped)electrically conductive connection 5 (that is implemented with thistesting apparatus).

According to FIG. 6, this testing apparatus 1 consists of a measuringchamber 2, a heat radiator 9, 9R, a positioning and fixing device 18, athermal (image) acquisition unit 11, 11R, a thermal (image) reproductionunit 13, 13R, a thermal (image) evaluation unit 15 and, if applicable,an external readout display screen 21 that are connected to one anotherby a circuit and/or related to one another.

The aforementioned functional elements and other means of the testingapparatus 1 according to FIG. 6, the reference symbols of which areprovided with the index “R,” respectively refer to a heat radiator 9Rfor infrared light that transfers thermal radiation 91R consisting ofinfrared light and, in addition, to thermal radiation 29R that consistsof infrared light and is emitted by the thermal field 12R of the crimpedelectrically conductive connection 5 that is derived from the thermalradiation 91R for infrared light, as well as to a thermal (image)acquisition unit 11R for infrared radiation and a thermal (image)reproduction unit 13R for infrared light.

This supplementary reference symbol index “R” is also used in thefollowing FIGS. 7 and 8 and their description.

One physical embodiment of said testing apparatus 1 is presented in FIG.5, wherein the functional elements of the testing apparatus 1 arepositioned within a chamber wall 4 for the measuring chamber 2, namelyin a housing region 16 of a housing 7 that borders the latter. Thethusly integrated housing 17 of the testing apparatus 1 has anappearance that corresponds or is at least very similar to that of acamera. In this case, the measuring chamber 2 features an apertureregion 2A that is framed by the chamber wall 4 on one side of themeasuring chamber and continued with the walls of the adjacent housingregion 16.

With reference to FIG. 6 that shows a block diagram and indicates theapproximate position of the circuit elements in the form of a side view,it may also be ascertained that the displaceable positioning and fixingdevice 18 is arranged on the bottom of the measuring chamber 2, whereinthe electrically conductive connection 5 that is realized by crimpingthe electric connecting elements (system elements 6, 7 and/or 8) andneeds to be tested for (an) existing contact deficiency (deficiencies)is fixed on said positioning and fixing device such that its verticaldistance from the chamber bottom may be varied. A heat radiator 9, 9R ispositioned near the chamber ceiling of the measuring chamber 2 at acertain vertical distance from the thusly positioned test arrangement(finished electrically conductive connection), wherein said testarrangement is subjected to the heat of the thermal radiation 9, 91, 91Rdirected thereon.

This may make it necessary to supply the heat radiator 9, 9R with energyfrom an energy source, for example, with the direct current IG of a d.c.generator or an accumulator, wherein said energy supply can beselectively interrupted with the aid of a first electric switch A. Thethermal field acquisition panel 20 is situated within the walls of thehousing region 16 near the aperture region 2A of the measuring chamber2, wherein the thermal field acquisition panel 20 is directed toward thetest arrangement (finished electrically conductive connection 5). Thelatter may be realized, for example, with heat sensors 19, 19R that aredistributed over the panel surface and able to optically capture(record) the thermal radiation 29, 29R of a thermal field 12, 12Remitted by the conductor insulation 62 of the system elements 6 and/or 8as well as the conducting components of the conductive (metallic) systemelements 6, 7 and/or 8 due to the accumulation of the applied heat,wherein the transferred thermal radiation 29, 29R of the thermal field12, 12R passes through the aperture region 2A of the plenum chamber 2and may ideally be directed straight on the thermal field acquisitionpanel 20 or the heat sensors 19, 19R distributed to over the panelsurface thereof and directly recorded.

Suitable downstream units for the signal conversion of the sensedthermal field 12, 12R are connected to the elements of the thermal fieldacquisition panel 20 or the heat sensors 19, respectively, and formintegral components of the thermal (image) acquisition unit 11, 11R.

The thermal field 12, 12R of the test arrangement that was acquired withsensors and converted, for example, into digital signals is transmittedvia an additional data line K to the thermal (image) reproduction unit13, 13R that reproduces a digitally illustrated thermal image of thetesting apparatus with possibly existing contact deficiencies of thetest arrangement (the crimped electrically conductive connection 5) withthe aid of an integrated thermal image reproduction panel 21B. Thethermal (image) reproduction unit 13, 13R is laterally arranged on theedge and above (on the cover surface of) the housing 17 of the testingapparatus 1, wherein the thermal image reproduction panel 21B is fittedinto a housing recess 21A in the cover surface of the housing 17 orpositioned underneath the recess 21A. This thermal (image) reproductionunit 13, 13R or thermal image reproduction panel 21B, respectively, mayalso (according to this example) be arranged at any other location ofthe housing, for example, laterally of the housing 17. The measuredvalues of the transferred thermal radiation of the thermal field 12, 12Athat provides information, among other things, on the temperatureconditions in the measuring chamber 2 during the test can also bedisplayed on said thermal image reproduction panel 21B.

In order to enable the thermal image reproduction panel 21B to alsodisplay other information in addition to the visual detection of a(correctly or incorrectly produced) electrically conductive connection 5in order to visualize not only the type, but also the extent (magnitude)of a contact deficiency, a thermal (image) evaluation unit 15 may beselectively connected to said thermal (image) acquisition unit 11, 11Rvia data lines H, M (outgoing and incoming lines). The latter maycomprise a (not-shown) storage unit, in which the digital nominal dataof a thermal image that pertains to contact deficiencies is retrievablystored.

This nominal data is electronically analyzed with the actual data of thethermal field 12, 12R of the test arrangement that was acquired with theaid of sensors and digitized, namely by a comparison device that formspart of the thermal (image) evaluation unit 15, wherein the (not-shown)comparison device transmits the result obtained from the comparison viaone of the data lines to the thermal (image) acquisition unit 11, 11R asshown in the example according to FIG. 6 in order to make this resultavailable to the thermal (image) reproduction unit 13, 13R. Otherwise,the comparison device of the thermal (image) evaluation unit 15 may alsodirectly transfer the result of the comparison between the nominal dataand the actual data to the thermal (image) reproduction unit 13, 13R.This makes it possible to visually output a determined length differenceΔ1 that was analyzed (determined) to be a contact deficiency or atolerated or non-existent length difference on the thermal imagereproduction panel 21B or on an external readout display screen 21connected to the thermal (image) reproduction unit 13, 13R, wherein thedetermined length difference

-   a) is selected between a conductor end 64 of the conductor 61 and/or    81 that is positioned within the socket cavity 72 and along the    socket axis E and the closed socket end at the socket outlet 74 or    between two opposite conductor ends within the socket cavity 72    and/or-   b) refers to the detection of an insulated conductor region    accommodated in the socket that is covered with insulation 62 and    assigned to a socket (crimping) surface B for crimping the    insulation that is positioned within the contact socket 71 along the    socket axis F and situated near the socket inlet 78.

FIGS. 7 and 8 respectively show an embodiment of the testing apparatus 1with a measuring chamber 2 according to FIG. 6 and a not shown adjacenthousing region 16 that is protected by walls and forms a completehousing 17 together with the measuring chamber. One may ascertain fromthe illustration in FIG. 7 that the heat radiator 9, 9R operatedaccording to the example shown in FIG. 6 emits thermal radiation 9, 9Rin the direction of the test arrangement [electric conductor 61,conductor insulation 62, contact socket 71 with illustrated socketcavity 72, as well as socket flange 76 arranged in the center of thesocket and (plug-type) socket extension 77 along the socket axis Fattached to the latter (to the right of the contact socket 71)], whereinthis thermal radiation heats the test arrangement and builds up athermal field 12, 12R that is optically captured by an optical device 23in the form of a lens and directed on a plane plate 22, the surface ofwhich is formed by two-dimensionally distributed heat sensors 27, withthe aid of an opened optical shutter device 28 that is released duringthe measuring phase and remains closed during the heating phase of thetest arrangement. If the times for the opening and closing function ofthe shutter device 28 are not observed, the function of thesensor-fitted plate 22 would be jeopardized because it cannot beprecluded that this plate is heated up (despite planned temperaturestabilization) such that the measuring sensitivity may be respectivelydiminished or impaired, comprised image data may be converted and faultyimages may be produced. Corresponding panel elements 25 for thetemperature stabilization are two-dimensionally distributed underneaththe plate 22 such that a “Focal Plane IR Panel with temperaturestabilization” is formed.

An electronics unit 24 arranged downstream of the heat sensors 27 isalso referred to as the “camera electronics” and completes the functionsof a thermal (image) acquisition unit 11, 11 R that is already knownfrom the description of FIG. 6. In addition, the distance a assumedbetween the lens and the plate 22 is shown. These figures also show theconnection between said electronics unit 24 and the thermal (image)reproduction unit 13, 13R, on the thermal image reproduction panel 21Bof which a readout display screen 21 with a graphic illustration isreproduced that pertains to an incorrectly produced electricallyconductive connection 5 according to the example shown in FIGS. 3C and4.

In contrast to the embodiment according to FIG. 7, the embodiment shownin FIG. 8 is designed for electrically heating the test arrangementdescribed with reference to FIG. 7 by means of an energy source(d.c./a.c.) such that the installation of a heat radiator 9, 9R may notbe required. All other functions of the test arrangement 1 describedwith reference to FIG. 7 are equally realized.

The presented testing apparatus 1 and the correlating method fordetecting a contact deficiency of an electrically conductive connection5 may be summarized in a simplified fashion as follows.

An electric conductor 61 that is incorrectly inserted into the contactsocket 71 results in an air gap Δ1 between the conductor end situatedwithin the socket cavity 72 and the contact socket. This air gap Δ1 hasan inferior coefficient of thermal conductivity in comparison with themetallic components of the electrically conductive connection 5(electric conductor 61, contact socket 71) that are connected bycrimping. Due to the heating of the crimp connection, thermography makesit possible to visualize whether an unacceptable air gap Δ1 is presentthat would result in inferior contacting of the connection 5. Inaddition, the converted deficiency image according to FIGS. 6-8 may makeit possible to deduce that a crimp of the conductor insulation (aninsulation crimp) that is realized, for example, according to FIG. 3Bhas an insufficient crimpable surface and therefore tends to develop thedescribed leaks of the electrically conductive connection 5 that areassociated with the risk of undesirable corrosion, for example, due tothe admission of atmospheric humidity or other corrosive gaseouspollutants into the socket cavity 72.

According to the example shown in FIG. 7, the following test steps of asimplified method for detecting contact deficiencies of a cableconnection may be carried out in the described sequence, wherein

-   a) the crimp connection 5 (electric conductor 61 with contact socket    71) is fixed in a measuring chamber 2;-   b) the cable connection 5 is then heated to a certain-temperature by    a heat radiator 9;-   c) the heating of the connection 5 is subsequently shut off after    the metallic components of the electrically conductive connection 5    have reached the temperature t;-   d) the optical shutter device 28 is then opened;-   e) a thermal image is recorded by means of a so-called IR array;-   f) the signal information of the IR array is subsequently converted    in an electronics unit 24 (in the camera electronics), and-   g) the thermal image is ultimately displayed on a thermal image    reproduction panel 21B (a screen).

With respect to the above-described method for detecting contactdeficiencies of a cable connection, the test step described below may besubstituted—referred to the illustration shown in FIG. 8—for step b) asfollows

-   h) the cable connection 5 with a generator-fed energy source 10    connected thereto is then supplied with a current and heated to a    certain temperature.

List of Reference Symbols  1 Testing apparatus  2 Measuring chamber  2ALateral aperture region  3 Aperture region (of measuring chamber 2)  4Chamber wall (of measuring chamber 2)  5 Electrically conductiveconnection  6 First system element 61 Electric conductor 62 Conductorinsulation 63 Marking (of conductor insulation 62)  7 Second systemelement 71 Contact socket 71A Contact socket 72 Socket cavity 72A Socketcavity 73 Socket wall 74 Closed socket outlet (socket end) 75 Inspectionhole (of contact socket 71) 76 Socket flange 77 Socket extension,plug-type 78 Socket inlet 78A Socket inlet  8 Third system element 81Electric conductor  9 Heat radiator  9R Infrared light heat radiator 91Transferred thermal radiation 91R Transferred thermalradiation--consisting of transferred infrared light 10 Energy source;generator; d.c. generator 11 Thermal (image) acquisition unit 11RThermal image acquisition unit for infrared light 12 Thermal field 12RThermal field--derived from thermal radiation for infrared light 13Thermal (image) reproduction unit 13R Thermal (image) reproduction unitfor infrared light 14 Fourth system element 141 Auxiliary socket; silversocket 14A Duplicate of fourth system element 14 141A Duplicate ofauxiliary socket 141; silver socket 15 Thermal (image) evaluation unit16 Housing region (of housing 17) protected by walls 17 Housing (oftesting apparatus 1) 18 Positioning and fixing device 19 Heat sensors 20Thermal field acquisition panel 21 Readout display screen 21A Housingrecess 21B Thermal image reproduction panel 22 Plate, plane 23 Opticaldevice; lens 24 Electronics unit 25 Panel element,temperature-stabilized 26 Heat sensor array 27 Heat sensors 28 Opticalshutter device 29 Thermal radiation 29R Thermal radiation A, D Switch BSocket (crimping) surface for insulation crimp C Conductor end region(of conductor 61, 81) F Socket axis G Index: generator H, M Data line IElectric current, constant K Data line S Air gap a Distance (plate22-optical device 23) b (Pre)defined length [of socket (crimping)surface B] l Stretched element length (of the system elements 6-8 in themeasuring chamber 2) l_(ISO) Required insulation length (of conductorinsulation 62)

1. A testing apparatus for detecting a contact deficiency of anelectrically conductive connection comprising a plurality ofelectrically conductive system elements having insulated and metalliccomponents for conducting signals or energy, the testing apparatuscomprising: a measuring chamber; a heat radiator; a thermal (image)acquisition unit; and a thermal (image) reproduction unit; wherein inthe measuring chamber the system components of the electricallyconductive connection are positioned, wherein the system components areconnected to one another in an electrically conductive fashion; whereinthe heat radiator is capable of being supplied with energy; wherein thetransferred thermal radiation of the heat radiator can be emitted intothe measuring chamber and the thermal radiation can be directed towardthe region of the system elements, such that a thermal field of theinsulated and the metallic system components of these connected systemelements is generated, wherein the thermal (image) acquisition unit isadapted for optically capturing the generated thermal field emitted bythe heated insulated and metallic system components of said connectedsystem elements and for realizing a signal conversion into a thermalimage of the connected system elements; wherein the thermal (image)reproduction unit is adapted for realizing a visual reproduction of theconverted thermal image; and wherein the thermal (image) acquisitionunit and the thermal (image) reproduction unit are connected in aninformation technological manner.
 2. A testing apparatus for detecting acontact deficiency of an electrically conductive connection comprising aplurality of electrically conductive system elements having insulatedand metallic components for conducting signals or energy, wherein thetesting apparatus comprises: a measuring chamber; a heat radiator; athermal (image) acquisition unit; and a thermal (image) reproductionunit; wherein in the measuring chamber the system components of theconnection are positioned; wherein the system components are connectedto one another in an electrically conductive fashion; wherein the heatradiator for infrared light can be supplied with a constant current by agenerator; wherein the infrared light thermal radiation of said heatradiator can be transferred transversely or horizontally or verticallyor in a deflected fashion and directed toward the region of theelectrically conductive connection, such that a thermal field of theinsulated and metallic system components of these connected systemelements can be generated by the infrared light thermal radiation;wherein the thermal (image) acquisition unit for infrared light isadapted for optically capturing the generated thermal field; wherein thethermal (image) acquisition unit is adapted for realizing a signalconversion into an infrared light thermal image of the conductivelyconnected system elements emitted by the heated insulated and metallicsystem components of these connected system elements; wherein thethermal (image) reproduction unit for infrared light is adapted forrealizing a visual reproduction of a digitally converted thermal image;and wherein the thermal (image) acquisition unit and the thermal (image)reproduction unit are connected in an information technological manner.3. The testing apparatus of claim 1 for use in the testing ofprefabricated cable connections installed in aircraft comprising atleast two electrically conductive system elements that are positionedwithin the measuring chamber, wherein the first system element comprisesan insulated electric conductor of an installation cable that is used asan aluminum conductor and a second system element comprises a rigidmetallic contact socket of an aluminum material or an aluminum alloy,the socket wall of which encloses a socket cavity that is closed at thesocket outlet on the outlet side of the socket cavity, wherein theelectric conductor, the conductor insulation of which is positioned onthe inlet side of the socket cavity underneath a socket (crimping)surface that is arranged on the circumference of the socket and limitednear the socket inlet when it is inserted therein, is arranged withinthe socket cavity with a stripped conductor end region that forms anextension of the conductor insulation, and wherein the contact socket ismechanically fixed on the conductor insulation by crimping the socket(crimping) surface of the socket wall and the stripped conductor endregion is connected to the contact socket in an electrically conductivefashion due to the crimping of the socket wall.
 4. The testing apparatusof claim 2 for use in the testing of prefabricated cable connectionsinstalled in aircraft comprising at least three electrically conductivesystem elements that are positioned within the measuring chamber,wherein the cable connection comprises a first and/or a third systemelement that is respectively realized with an insulated electricconductor of an installation cable used as an aluminum conductor, aswell as a second system element that is realized with a rigid metalliccontact socket of an aluminum material or an aluminum alloy, wherein therespective electric conductor, the conductor insulation of which ispositioned on the inlet side of the socket cavity underneath a socket(crimping) surface that is arranged on the circumference of the socketand limited near the socket inlet when it is inserted therein, isarranged within the socket cavity with a stripped conductor end regionthat forms an extension of the conductor insulation, and wherein thecontact socket is mechanically fixed on the conductor insulation bycrimping the socket (crimping) surface of the socket wall and thestripped conductor end region is connected to the contact socket in anelectrically conductive fashion due to the crimping of the socket wall.5. The testing apparatus of claim 1, wherein the thermal (image)acquisition unit for detecting contact deficiencies that indicate anincorrectly produced conductive connection is connected to a thermal(image) evaluation unit with respect to information technology, andwherein the thermal (image) evaluation mark can be selectively connectedto the thermal (image) acquisition unit in order to determine deviationsbetween nominal data and actual data of the conductive connection and torealize the conversion of these deviations that predominantly pertain tocontact deficiencies detected by determining a length difference (Δl)between a conductor end of the conductor that is positioned within thesocket cavity and along a socket axis and a closed socket end at thesocket outlet or between two opposite conductor ends within the socketcavity and/or by detecting an insulated conductor region accommodated inthe socket that is covered with a conductor insulation and assigned to asocket (crimping) surface for the insulation crimp that is situatedwithin the contact socket along the socket axis and positioned near thesocket inlet.
 6. The testing apparatus of claim 1, wherein an apertureregion that can be tightly sealed relative to escaping radiation isarranged in a chamber wall of the measuring chamber, and wherein theelectrically connected system elements can be inserted through theaperture region.
 7. The testing apparatus of claim 6, wherein thechamber wall contains at least one aperture region.
 8. The testingapparatus of claim 6, wherein the thermal (image) acquisition unit, thethermal (image) reproduction unit, the thermal (image) evaluation unitand the heat radiator are positioned within a housing region that isprotected by walls and extended by the chamber wall of the measuringchamber.
 9. The testing apparatus of claim 6, wherein the chamber walland the housing region protected by walls form integral components of ahousing of the testing apparatus that is protected against escapingradiation.
 10. The testing apparatus of claim 8, wherein the measuringchamber is arranged upstream of the thermal (image) acquisition unit.11. The testing apparatus of claim 1, wherein a positioning and fixingdevice is arranged within the measuring chamber such that it can bedisplaced horizontally or vertically or transversely, with saidpositioning and fixing device making it possible to fix and change theposition in space of the electrically connected system elements.
 12. Thetesting apparatus of claim 1, wherein the thermal (image) acquisitionunit is equipped with a plurality of two-dimensionally distributedoptical heat sensors or with a thermal field acquisition panel that arefunctionally able to capture the transferred thermal radiation andconnected to downstream units for the signal conversion of the thermalfield.
 13. The testing apparatus of claim 1, wherein the thermal (image)reproduction unit and the thermal (image) evaluation unit arerespectively connected to a data line that is connected with respect toinformation technology to an additional data line connected to thethermal (image) acquisition unit.
 14. The testing apparatus of claim 1,wherein the thermal (image) acquisition unit and the thermal (image)reproduction unit or the thermal (image) acquisition unit and thethermal (image) evaluation unit and the thermal (image) reproductionunit are connected with respect to information technology.
 15. Thetesting apparatus of claim 1, wherein the heat radiator is realized inthe form of an infrared radiator and serves for realizing the radiantinfrared light heating of the connected system elements by means of theinfrared radiation transferred by the infrared radiator.
 16. The testingapparatus of claim 1, wherein the heat radiator is realized in the formof a halogen radiator for radiant heating of the connected systemelements by means of the thermal radiation transferred by the halogenradiator.
 17. The testing apparatus of claim 1, wherein the thermal(image) acquisition unit and the thermal (image) reproduction unit andthe thermal (image) evaluation unit are embodied in an infrared lightcamera.
 18. The testing apparatus of claim 1, wherein the thermal(image) acquisition unit and/or the thermal (image) reproduction unitand/or the thermal (image) evaluation unit comprises a peripheraldevice.
 19. The testing apparatus of claim 1, wherein the thermal(image) reproduction unit is equipped with a thermal image reproductionpanel that is arranged underneath or within a recess in the housing ofthe testing apparatus.
 20. The testing apparatus of claim 19, wherein adata line connected to the thermal (image) acquisition unit and thethermal (image) reproduction unit by a second switch serves forconnecting at least one peripheral device, preferably a readout displayscreen for illustrating the thermal image.
 21. The testing apparatus ofclaim 1, wherein the thermal (image) acquisition unit comprises a planeplate that is used as the focal plane for an optical device, the opticaldevice and an electronics unit, wherein a temperature-stabilized panelelement is fixed on the plate in a plane fashion underneath the focalplane, wherein an infrared light sensor array, composed of comprising aplurality of infrared light sensors, is integrated into the plate insuch a way that a plate surface that is arranged at a distance from saidoptical device and directed toward the measuring chamber is suitable forproducing a surface-distributed sensitive recording of the thermal fieldgenerated by the thermal radiation transferred by the latter, andwherein the heat sensors of the plate are connectable to the electronicsunit that supplies the thermal image supply unit with respect toinformation technology after the signal conversion of the sensitivelyacquired thermal radiation has been performed.
 22. The testing apparatusof claim 21, wherein an optical shutter device is arranged between theoptical device and the plane plate for interruption of the radiationpath of the transferred thermal radiation.
 23. A method for detecting acontact deficiency of an electrically conductive connection that isadapted for the testing of electrically conductive system elements usedfor conducting signals or energy; wherein a plurality of seriallyconnected system elements are connected in an electrically conductivefashion by a crimp connection at the connecting points of the systemelements; wherein the method utilizes a testing apparatus, thefunctional scope of which comprises a measuring chamber, a heat radiatorthat is supplied with energy and arranged within the latter, a thermal(image) acquisition unit and a thermal (image) reproduction unit thatare connected in an information technological manner; and wherein themethod comprises: a) positioning the system elements that are seriallyconnected by crimp connections in the measuring chamber; b) transferringthermal radiation toward the region of the system elements in themeasuring chamber by the heat radiator; c) transferring thermal energyof the thermal radiation to insulated and metallic system components ofthe connected system elements such that a thermal field is generated; d)optically capturing the thermal (image) acquisition unit andsubsequently converting the generated thermal field by a signalconversion into a thermal image; and e) displaying a visual reproductionof the converted thermal image by the thermal (image) production unit.24. The method of claim 23, wherein the metallic system components ofthe connected system elements are, with the exception of step b), heatedby current heating, and wherein the current heating of the connectedsystem elements is realized with a controllable energy source that isconnected to the serially connected system elements and forms a circuit.25. The method of claim 23, wherein the thermal (image) acquisition unitis connected to a thermal (image) evaluation unit after step d) in astep f) subsequent to step c), wherein the thermal (image) evaluationunit can be selectively connected to the thermal (image) acquisitionunit and serves for detecting and, if so required, transmitting allcontact deficiencies indicating an incorrectly produced electricallyconductive connection to the thermal (image) acquisition unit before thesignal conversion into a thermal image is carried out.
 26. The method ofclaim 25, wherein the contact deficiencies according to step f) aredetected by determining the deviations between nominal data and actualdata of the produced electrically conductive connection in the form of acomparison between a nominal value based on a correctly producedconnection that is stored in an internal storage unit of the thermal(image) evaluation unit and an actual value based on an incorrectlyproduced connection that is obtained by the thermal (image) acquisitionunit with the thermal image signal conversion data of these seriallyconnected system elements and retrievably transmitted to the thermal(image) evaluation unit.
 27. The method of claim 26, wherein the storednominal value of an incorrectly produced electrically conductiveconnection and its obtained actual value g) are related to a permissibledeviation of a length difference (Δl) between a conductor end of aconductor that is situated within a socket cavity and positioned alongthe socket axis and a closed socket end [at the socket outlet] orbetween two opposite conductor ends within the socket cavity and/or h)related to a required insulation length of a section of a conductorinsulation that is used as a socket (crimping) surface and assigned toan insulated conductor region accommodated in the socket that issituated within the socket cavity of the contact socket along the socketaxis and correlated with an insulation-backed socket region extending asfar as the vicinity of the socket inlet.